The Hermes Express is the Olympian equivalent of a courier/messenger service, run by Hermes.
Percy Jackson and the Olympians[]
The Lightning Thief[]
Percy Jackson uses the Hermes Overnight Express to send the head of Medusa back to Mount Olympus after he beheaded her in the battle at Aunty Em's Gnome Emporium. Later, he finds the same package in his bedroom marked "Return to Sender" sent back by Poseidon.
The Sea of Monsters[]
Hermes mentions to Percy that the Overnight Express business is booming, and later Poseidon also uses the service to send Percy a letter, which Hermes personally delivered.
The Heroes of Olympus[]
The Demigod Diaries[]
Percy Jackson and the Staff of Hermes[]
While Percy is celebrating his one month anniversary with Annabeth Chase, a Hermes Express truck appeared on the lawn in front of them. No one else in the area noticed it except them. Hermes enlisted Percy to find his Caduceus so he could make his deliveries on time. Percy retrieved the staff and Hermes finished his deliveries.
The Mark of Athena[]
When Annabeth Chase is on her quest for the Mark of Athena under the city of Rome, she stumbles across a box from Hermes delivery services. She is excited, because it may be something to help with her quest. When she opens the crate, however, all that is left inside is bubble wrap. Annabeth later realizes it was a gift and uses it as gauze for her broken ankle.
Percy Jackson and the Olympians[]
The Chalice of the Gods[]
Percy suggests just using Hermes Express to send Ganymede's Chalice back to the godly cupbearer, recalling that Hermes Express has one-hour delivery in Manhattan. However, Ganymede needs his chalice immediately and, as the leader of the quest, it's Percy's job to hand deliver the chalice as per the rules regarding quest completion.
Wrath of the Triple Goddess[]
After finding Percy and Grover gift-wrapping Silbe, Annabeth asks Percy to tell her that they're wrapping Silbe up to Hermes Express her to Mount Olympus. Percy realizes that she's referencing the time that he had mailed Medusa's Head to Olympus and reassures his girlfriend that they're not going to do that.
Percy Jackson and the Olympians (TV series)[]
"We Visit the Garden Gnome Emporium"[]
Percy Jackson uses Hermes Express to mail Medusa's Head to Olympus where it's personally delivered to the gods by an amused Hermes.
"The Prophecy Comes True"[]
Gabe Ugliano discovers that the gods have shipped back to Percy the box containing Medusa's Head. When Gabe opens the box and looks inside, he is instantly turned to stone.